It pays the rent
No doubt things are tough when you are a defeated Presidential and Senatorial candidate with seven children to support, like Rick Santorum ,  and you have to prioritize.
Priority #1 is snuggling up to the Israel lobby: Rick Santorum Launches Effort To Defeat Chuck Hagel Nomination By Donna Cassata, The Huffington Post, January 10, 2013. Santorum has always been very aware this is lucrative, actually opening his Presidential run with a naked appeal for their backing as I noted in Rick Santorum Running For President Of....Israel? 
Priority #2 apparently is helping the GOP run up the white flag on Immigration Rick Santorum: 'Republicans Are Ready To Do Something On Immigration' by Alana Horowitz The Huffington Post 1/20/2013
Rick Santorum suggested on Sunday that Republicans are ready to tackle immigration reform.
"I think the Republicans are ready to do something on immigration," he said on ABC's This Week.
The writer drily notes Santorum
…has taken a softer tone on the issue since ending his campaign. In December, he said that the U.S. needs immigration.
“I think the fact that we send some of those people back and don’t give them the opportunity to participate here is wrong," Santorum told Politico .
You might think after Romney’s Israeli grovel  cost him the Paul vote  and probably that of many white blue collar women  a more relevant subject for discussion would be need to scale back the GOP’s War Party image - rather than outraging and driving away the Patriot element of Republican community by betraying them on the swamping of the country.
That would show you have not grasped what motivates these Conservatism Inc. scavengers . They see Sheldon Adelson , Bill Kristol  and their friends are where the money is.
And nothing else counts.